AC compressor

KHAL

MEMBER
2001 OLDSMOBILE AURORA
3.5L
6 CYL
2WD
AUTOMATIC
100,500 MILES

Hello, I recently started troubleshooting my AC system to see what could be the cause of it only blowing warm air. It was blowing reasonably cool air last year, however it was not nearly as cold as when I first got the car six years ago. I noticed the clutch was not turning on when I looked at it. Did an evac and recharge to the recommended value in the owners manual on the Freon to see if maybe it was too low to trigger the pressure switch to engage compressor. Even after that is done, the compressor will not work. There is power going to the unit. Does this warrant a replacement? Or is there a repair on the compressor I can try or something else that could be causing the compressor to not be working?

6 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good afternoon.

Do you mean it has power to the compressor clutch?

Roy

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Friday, April 27th, 2018 AT 12:33 PM

STEVE W.

MECHANIC
13,560 POSTS

If you have twelve volts at the clutch connection but the clutch is not engaging it is very likely the coil is burnt out. Double check that the ground wire is good but the clutch can be replaced on that compressor, although it is usually cheaper to replace the entire compressor and clutch these days.

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Friday, April 27th, 2018 AT 12:39 PM

KHAL

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3 POSTS

There is twelve volts to the harness connector on the top of the compressor when I checked it the wiring at the connector. I know just enough about cars to get into trouble, but I have done a fair amount of research and troubleshot what I could.

To describe what I am seeing on my end is, the pulley system on the serpentine belt works great, it spins smoothly without shaking. Bearings seem to be fine based on that assessment as well. The compressor does spin freely when hand rotated, so it is not locked up. The clutch does not engage on the compressor when AC is turned on to lowest setting. There is power to the connector on the compressor unit. I have swapped fuse and relay for the AC clutch just in case as well.

I got a quote from a service center near me for $1,490.00 to replace the compressor plus evac and recharge. To me personally after looking at the cost for a new part ($680.00) and how reasonably simple it is to get to the compressor on my vehicle (remove one pulley on serpentine array, unmount but not remove alternator and that is it), I think that is one hell of a ripoff.

So what I am looking at is repairing it myself if possible. Or try out more troubleshooting options to isolate problem if there is any. I will have to check the ground on that coil, will need to research how exactly to do that.

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Friday, April 27th, 2018 AT 1:09 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Okay, you need a compressor. The estimate is very high.

The part is around 350-475. The dryer is about 75. Pag oil is about 15.

Freon is about $25.00.

The labor is about five hours including the evac and charge.

That comes up to around $1,100.00.

Shop around for a better price. That price is very high.

Roy

procedures:

1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging.
2. Remove the drive belt.
3. Raise and support vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
4. Remove the right front tire and wheel assembly.
5. Remove the front air deflector. Refer to Air Deflector Replacement - Front in Body Front End.
6. Remove the right wheelhouse extension. Refer to Wheelhouse Extension Replacement in Body Front End.
7. Support the front of the cradle with a floor jack.
8. Remove the right front cradle bolt and lower the cradle.
9. Remove the idler pulley and bolt.

IMPORTANT: Seal the A/C compressor suction and discharge ports after the hoses are removed in order to keep the A/C compressor oil from draining out of the compressor during removal.

All A/C lines hoses and components should be sealed after removal in order to avoid excessive moisture contamination to the A/C system during servicing.

10. Disconnect the suction hose fitting from the compressor.

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11. Disconnect the discharge hose fitting from the compressor.
12. Remove the upper generator mounting bolts and position the generator out of the way in order to access the compressor mounting bolts.

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13. Disconnect the compressor electrical connector.

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14. Remove the upper compressor mounting bolts (1).
15. Position the generator and install the idler pulley bolt to hold the generator in place.
16. Loosen the rear nut (2) and remove the front nut (3).
17. Remove the compressor from the engine block.
18. Rotate the compressor, in order to allow the A/C compressor to exit through the wheelhouse opening.
19. Remove the compressor from the vehicle.

INSTALLATION PROCEDURE

IMPORTANT: When replacing the compressor it is necessary to drain and measure the old compressor oil (be sure to rotate the shaft to ensure a complete draining). Drain the oil from the new compressor and add the amount taken from the old compressor. Refer to Refrigerant System Capacities.

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1. Install the A/C compressor through the wheelhouse opening and position on the front (4) and rear (5) studs.
2. Remove the generator idler pulley bolt and position generator out of the way.

NOTE: Refer to Fastener Notice in Service Precautions.

3. Install and hand tighten the bolts (1) and nuts (2, 3).

Tighten
Tighten the A/C compressor front nut (3) to 50 N.M (37 lb ft).
Tighten the A/C compressor mounting bolts (1) to 50 N.M (37 lb ft).
Tighten the A/C compressor rear nut (2) to 25 N.M (18 lb ft).

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4. Connect the compressor electrical connector.
5. Install the generator mounting bolts.

Tighten
Tighten the generator bolts to 50 N.M (37 lb ft).

IMPORTANT: Inspect the seal washers for damage before reinstalling the A/C lines and hoses.

If any damage is noted during inspection, the suspect seal must be replaced.

Flat washer type seals do not require lubrication.

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6. Connect the discharge hose fitting to compressor.

Tighten
Tighten the discharge hose nut to 20 N.M (15 lb ft).

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7. Connect the suction hose fitting to the compressor

Tighten
Tighten the suction hose nut to the compressor to 20 N.M (15 lb ft).

8. Install the idler pulley and bolt.
9. Raise the right front cradle and install the bolt.

Tighten
Tighten the bolt to 191 N.M (141 lb ft).

10. Install the drive belt.
11. Install the right side AIR pump.
12. Install the wheelhouse extension. Refer to Wheelhouse Extension Replacement in Body Front End.
13. Install the front air deflector. Refer to Air Deflector Replacement - Front in Body Front End.
14. Reinstall the right front tire and wheel assembly.
15. Lower the vehicle.
16. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging.
17. Leak test the fittings of the component using the J 39400-A.

You will need a recovery machine for the removal of the freon.

Replace the receiver/dryer as well. It would also be good to replace the orfice tube in line as well.

Roy

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Friday, April 27th, 2018 AT 1:22 PM

KHAL

MEMBER
3 POSTS

Roy,
Thank you for assisting me in isolating the problem, I have been researching for many days and many hours this week and got as narrow of a scope for part failure as I could as a relatively inexperienced person on car repair.

I appreciate the advice to shop around and a more reasonable cost estimate than roughly half the cars current selling value in my area like the service center had. I have worked two years as an aircraft electrician and had to install and remove many different components. Based on these procedures, I think this may be something I can do. But just in case I find a better deal elsewhere, I will see what other car shops have to offer in my area.